A while ago I used Windows XP Mode to create VMs with different versions of IE for testing - very easy if you have Windows 7 Pro because XP mode can be duplicat

A while ago I used Windows XP Mode to create VMs with different versions of IE for testing - very easy if you have Windows 7 Pro because XP mode can be duplicated/copied around like any other VM and has automagic licensing provided the host in Windows 7 Pro (if you move the VM to a different type of host it will fail to work) Obviously this is only good if you're already on windows but that was a huge help for development and didn't take much effort to set up.